1. Field of the Invention
The present invention relates to a sheet registration apparatus in an image forming apparatus such as a copying machine, a printer or an ordinary paper facsimile, for stacking a plurality of imaged sheets and registering the stacked sheets.
2. Description of the Related Art
In copying machines, printers, ordinary paper facsimile apparatuses or the like, desired images are formed on the sheets, and the imaged sheets are discharged to the outside of the apparatus. Some of such apparatuses are equipped with an apparatus for post-treating or stapling a plurality of imaged sheets into a bundle.
Such image forming apparatus equipped with the sheet post-treating apparatus is disclosed in Japanese Examined Patent Publication JP-B2 7-25469 (1995), for example. FIG. 38 is a perspective view showing the sheet post-treating apparatus 200 such as a sorter, which is arranged to have its receiving mouth at such a portion of the image forming apparatus as to discharge the imaged sheets. The sorter 200 is equipped with a number of sort bins 201 which are provided for sorting the sheets discharged.
In the sorter 200, the numerous sorting sort bins 201 are arranged in a vertically stacked state for stacking the discharged sheets sequentially on their upper faces. The individual sort bins 201 are arranged so as to vertically move to the position corresponding to the sorting exit of the image forming apparatus, for example, to receive the sheets, as discharged from the exit. The sort bins 201 are guided at their leading end portions in the sheet discharge direction, when moved up and down, by a support member for uniting the sort bins and are connected at their opposite end portions on the side of the exit to a lift mechanism 203 so that the sort bins 201 are moved up and down according to the turning direction of the lift mechanism 203.
When the sheets to be sorted are discharged, the sort bins 201 are ascended or descended by the lift mechanism 203 thereby to position each sort bin 201 at the sorting exit, and the sheets are discharged to the sort bins 201, as sequentially assigned. In order that the one-side end edges, as perpendicular to the discharge direction, of the sheets discharged to the individual sort bins 201, may be registered to a regulation member 204, the sorter 200 is equipped with a registration apparatus 205 having a registration rod 206 which is made movable to the opposite side of the registration member 204.
In the registration apparatus 205, the vertical registration rod 206 is provided arcuate openings 201a which are so formed in advance in the individual sort bins 201 as to extend through all the sort bins 201. The registration rod 206 is connected at its two end portions to the individual oneend portions of arms 207 to be turned. The other end portions of the individual arms 207 are individually fixed on not-shown pins, which are connected to a rotary drive motor or the like so that they are turned.
As a result, the registration rod 206 is turned through the arms 207 so that the individual sheets, as discharged to and stacked on the sort bins 201, are moved toward and registered by the regulation member 204. The sheets thus registered are stapled, if necessary. For this stapling operation, a stapling unit 209 is arranged at one-corner portions of the individual sort bins 201 of the sorter 200. The stapling unit 209 is relieved from a predetermined stapling position, when the sort bins 201 are vertically moved, and is moved to the stapling position when in the stapling process.
In the sorter 200 provided with the sheet post-treating apparatus device such as the stapling function, as shown in FIG. 38, the imaged sheets, as delivered from the image forming apparatus, can be registered, when discharged to the sort bins 201 designated to the sorting destinations, by the registration apparatus 205 to have their one-side end edges arranged with the regulation member 204 on the sort bins 201. After completion of this registration, the sheets are stapled by the stapling unit 209, if necessary.
For the stapling operation or the like, according to the prior art thus far described, the bundles of sheets discharged and stacked on the individual sort bins 201 by the registration apparatus 205 or the discharge trays have to be arranged and registered by the registration member 204. Without satisfactory registration, the stapling operation, if done, cannot fix the stapling position. As a result, some sheets are left non-stapled and may fall down or may be left as they are, when the sheet bundles are removed from the sort bins 201. The unfixed stapling position gives an unsatisfactory appearance.
According to the registration apparatus 205 of the prior art, moreover, the sheets are registered such that they are pushed by the registration rod 206 to the regulation member 204, as opposed to the registration rod 206. As a result, the sheets may often fail to be arranged at their one-side end edges (e.g., their trailing ends) at the end portions to be stapled, especially on the side to confront the exit. Thus, there arises a trouble that the stapling state is not satisfactory.
The other end edges perpendicular to the one-side end edges could also be arranged if a second registration rod for pushing the sheets from the side opposed to the sheet trailing end portions were added to the registration rod 206. With this construction, however, it is necessary to additionally provide a registration apparatus for moving the second registration rod, so that the entire registration apparatus is large-sized to enlarge the post-treatment device as a whole and to raise the cost.